A
radar detector is a passive electronic device used by
motorists to detect if their speed is being monitored by a
radar unit. Most radar detectors are used so the driver can reduce the car's speed before being
ticketed for speeding. Only
doppler radar-based devices can be detected — other speed measuring devices including those using
ANPR,
piezo sensors, and
VASCAR technology cannot be detected.
LIDAR devices require a different type of sensor, although many modern detectors include LIDAR sensors. Most of today's radar detectors detect signals across a variety of wavelength bands: usually
X,
K, and
Ka. In Europe the
Ku band is common as well.
Description
One of the technologies that law enforcement agencies can use to measure the speed of a moving vehicle uses
doppler radar to beam a
radio wave at the vehicle, and then infer the vehicle's speed by measuring the
Doppler effect-moderated change in the reflected wave's frequency.
Radar guns can be hand-held, vehicle mounted or mounted on a fixed object, such as a
traffic signal.
Radar detectors use a superheterodyne receiver to detect these electromagnetic emissions from the radar gun, and raise an alarm to notify the motorist when a transmission is detected. False alarms can occur however due to the large number of devices, such as automatic door openers (such as the ones at supermarkets), that operate in the same part of the electromagnetic spectrum as radar guns.
In recent years some radar detectors have added GPS technology. This allows users to manually store the locations where police frequently monitor traffic, with the detector sounding an alarm when approaching that location in the future (this is accomplished by pushing a button and doesn't require coordinates to be entered). These detectors also allow users to manually store the coordinates of sites of frequent false alarms, which the GPS enabled detector will then ignore. Some GPS enabled detectors can download the GPS coordinates of speed monitoring cameras and redlight cameras from the internet, which are contained in the Trinity database. A traveler from out of state, passing through Arizona for example, would receive an alarm when approaching the location of a speed monitoring camera.
Counter technology
Radar guns and detectors have evolved alternately over time to counter each other's technology in a form of civilian
electronic "warfare". For example, as new frequencies have been introduced, radar detectors have initially been "blind" to them until their technology too has been updated. Similarly, the length of time and strength of the transmissions have been lowered to reduce the chance of detection, which in turn has resulted in more sensitive receivers and more sophisticated software counter technology. Lastly, radar detectors may combine other technologies, such as
GPS-based technology with a
point of interest database of known
speed trapping locations, into a single device to improve their chances of success.
Radar detector detectors
The superheterodyne receiver in radar detectors has a local oscillator that radiates slightly, so it is possible to build a radar-detector detector, which detects such emissions (usually the frequency of the radar type being detected, plus about 10 MHz). The VG-2 Interceptor was the first device developed for this purpose, but has since been eclipsed by the Spectre III. This form of "electronic warfare" cuts both ways - since detector-detectors use a similar superheterodyne receiver, many early "stealth" radar detectors were equipped with a radar-detector-detector-detector circuit, which shuts down the main radar receiver when the detector-detector's signal is sensed, thus preventing detection by such equipment. This technique borrows from ELINT surveillance countermeasures. In the early 1990s, BEL-Tronics, Inc. of Ontario, Canada (where radar detector use is prohibited) found that the local oscillator frequency of the detector could be altered to be out of the range of the VG-2 Interceptor. This resulted in detector manufacturers responding by changing their local oscillator frequency. Today, practically every radar detector on the market is immune to the VG-2 Interceptor.
Radar scrambling
Although some companies advertise that their radar detectors can
passively 'scramble' or 'absorb' radar (such as Rocky Mountain Radar), many or all of their products do not affect radar and laser equipment due to the low power intake from the device versus the high power that bounces off a vehicle.
It is illegal in many countries to sell or possess any products that actively transmit radar signals intended to jam radar equipment. In the United States, actively transmitting on a frequency licensed by the Federal Communications Commission (FCC) without a license is a violation of FCC regulations, which may be punishable by fines up to $10,000 and/or up to one year imprisonment.
LIDAR Detection
Newer speed detection devices use pulsed
laser light, commonly referred to as
LIDAR, rather than
radio waves. Radar detectors, which detect radio transmissions, are therefore unable to detect the
infrared light emitted by LIDAR guns so a different type of device called a
LIDAR detector is required. LIDAR detection, however, is not nearly as effective as radar detection because the output beam is very focused. While radar's radio waves can expand to across at from their source, LIDAR's light beam diffuses to only about . Also, a police officer targeting a car will most likely aim for the center mass or headlight of the vehicle and, because radar detectors are mounted on the windshield away from the beam's aim, they may not alert at all. Lastly, with such a focused beam, an officer using a LIDAR gun can target a single car in close proximity to others at ranges of up to .
Despite the advent of LIDAR speed detection, radar remains more prevalent because of its lower price relative to LIDAR equipment and the amount of radar equipment already in service.
Legality
Using or possessing a radar detector or jammer is illegal in certain countries, and it may result in fines, seizure of the device, or both. These prohibitions generally are introduced under the premise that a driver who uses a radar detector will pose a greater risk of accident than a driver who does not. However the
2001 Mori report suggests that radar detector users posed a 28% less risk of accident. The table below provides information about laws regarding radar detectors in particular nations. In 1967 devices to warn drivers of radar speed traps were being manufactured in the United Kingom; they were deemed illegal under the
Wireless Telegraphy Act 1949.
{| class="wikitable"
|-
! Country
! Legality
! Comment
! Radar Bands
|-
| Australia
| Illegal in all states besides Western Australia
| They are illegal to use in a moving vehicle (as stated by the traffic laws in) SA, NSW, ACT and Victoria as well as NT, Queensland and Tasmania. Heavy fines apply, ranging from $200 – $1200 AUD, up to 9 demerit points, and confiscation of the Radar Detector. However, importing a unit is permitted under Australian customs regulations. Queensland = up to 40 penalty units (x$75 =$3000) for being in or on a vehicle whether or not the device is operating or in working order.
|K, Ka, Laser
|-
| Belgium
| Illegal
| In July 2006, a provisional seizure of a vehicle worth over 75.000 EUR itself was ordered by the courts, destruction of the radar detector itself and the driver's license was suspended for 3 months.
|-
|Brazil
|Illegal in all states.
|
|-
|Bulgaria
|Detectors legal, jammers illegal.
|Radar jammers are illegal.
|X, K (fixed camera+radar)
|-
|Canada
|
Illegal: Newfoundland & Labrador, Nova Scotia, Prince Edward Island, New Brunswick, Quebec, Ontario, Manitoba, the Yukon Territory, the Northwest Territories:
Legal: Alberta, British Columbia, Saskatchewan
|Regardless of whether they are used or not, police there may confiscate radar detectors, operational or not, and impose substantial fines in provinces where radar detectors are illegal.
|
|-
|
Croatia
|Detectors and jammers are illegal.
|
HRK 2000 (€ 270) fine.
|
|-
|
Czech Republic
|Detectors legal, jammers illegal.
|Fine up to CZK 200,000 (€ 7750), penalty points.
|Ka
|-
|
Egypt
|Detectors and jammers are illegal.
|
|-
|
Estonia
|Illegal to use or have in a motor vehicle.
|Fine up to 18000 EEK (€ 1150) as well as confiscation of the device.
|-
|
France
|*Illegal
|Regardless of whether they are used or not, police there may confiscate radar detectors, operational or not, and impose substantial fines.
|-
|
Finland
|Illegal to use or have in a motor vehicle on a public road.
|The fine depends on income. The detector will be confiscated.
|POP Ka
|-
|
Germany
|Legal to own, illegal to use in a moving vehicle
|75€ fine , 4 Points, destruction of the radar detector.
|-
|
Greece
|Illegal
|2000€ fine , 30 day driver's license suspension, 60 days car registration license suspension and 5 SESO penalty points
|-
|
Hungary
|Legal, no limitations
|
|-
|
India
|Legal
|
|-
|
Iceland
|Legal
|Radar jammers are illegal.
|-
|
Ireland
|Illegal (Republic of Ireland, Éire)
|Law Refers to 'Speed Meter Detectors', Introduced 1991. No fixed penalty for possession, expect confiscation and Hefty fine.
|-
|
Israel
|Legal
|Some cellular providers such as
Pelephone actually provide radar detecting as a service powered by
GPS
|-
|
Italy
|Illegal
|
|-
|
Japan
|Legal
|
|-
|
Jordan
|Illegal
|Regardless of whether they are used or not, police there may confiscate radar detectors, operational or not.
|Laser (possibly others)
|-
|
Latvia
|Illegal
|
|K, POP Ka
|-
|
Lithuania
|Illegal
|
|X, POP K, Laser
|-
|
Malaysia
|Illegal to possess, purchase, sell or use. Heavy fines apply.
|Radar detectors are also prohibited items under customs laws.
|-
|
Netherlands
|Illegal
|250€ fine and seizure of the device (since 2004)
|-
|
New Zealand
|Legal
|Ka and Laser used also fixed speed camera and speed camera vans (Low Powered K Band)
|-
|
Norway
|Illegal to use. (Legal to own, sell, and buy)
|8000-10000
krone fine and seizure of the device.
|-
|
Pakistan
|Legal
|
|-
|
Poland
|Legal to own, illegal to use in a moving vehicle
|Jammers illegal
|X, K, Pulse K, Ka Narrow, Laser
|-
|
Romania
|Legal since 2006
|Radar jammers still illegal
|Instant-On K
|-
|
Russia
|Legal
|
|Instant-On (Pulse) X, POP K, Laser (0,8 mkm)
|-
|
Saudi Arabia
|Illegal
|
|-
|
Serbia
|Illegal to use, possess, sell or advertise
|Illegal to use or have in possession in a vehicle in traffic, to sell or advertise: an apparatus or any other means of detecting or interfering with operation of vehicle speed measuring devices, or any other apparatus used for discovering and reporting traffic violations
|-
|
Singapore
|Illegal to possess, purchase, sell or use. Heavy fines apply.
|Radar detectors are also prohibited items under customs laws.
|-
|
South Africa
|Illegal to use in a moving vehicle
|Importing a unit is permitted under South African
customs regulations.
|-
|
Spain
|Radar Detectors legal, jammers illegal.
|Radar and Laser jammers fine up to 6000€
|Ka narrow, laser, Autovelox
|-
|
Switzerland
|Illegal
|Radar detectors are confiscated and destroyed. The use of any
GPS-based device to locate speed cameras is also illegal.
|-
|
Turkey
|Illegal
|Radar jammers are illegal
|-
|
UAE
|Illegal
|
|-
|
United Kingdom
|Legal
|Legal to own, but technically illegal to use under the
Wireless Telegraphy Act 1949 until 1998, due to legal loophole causing them to be legalized suddenly.
|-
|
United States
|Law varies from state to state, but detectors are generally legal in private vehicles under the
Communications Act of 1934 and illegal in commercial vehicles by
DOT regulation (
49 CFR 392.71). Exceptions:
Illegal in all vehicles: Virginia, Washington D.C., U.S. military bases
Illegal in commercial vehicles under state law:
Illinois,
New York,
New Jersey (specifically, commercial vehicles over and
all vehicles over ) Also illegal in all commercial vehicles over 10000 lbs under US federal law
Prohibitions against affixing items to windshield - "obstructing vision"):
Minnesota,
California
Repealed:
Connecticut (repealed in 1992)
|Confiscation and/or destruction of the detector was once a common practice but lawsuits raised by drivers arguing violation of property rights have resulted in temporary removal while a citation is written, then return of the device after its description (make, model and serial number) has been entered on the ticket - usually for speeding and possession/operation of detector. Use of a radar/lidar detector on a military installation is prohibited. Persons entering a military installation with one visibly mounted to the sun visor or windshield will be asked to remove it and put it away. Those who refuse will be denied entry onto the installation at that time. Military law enforcement may not solely stop a vehicle for a detector being in use but, along with being stopped for another moving violation, the person using the detector may be ordered to report the violation to his/her unit commanding officer (active duty ONLY).
Radar jammers are illegal under federal law, but laser jammers aren't specifically banned. Some states, such as Minnesota, have state laws banning laser jammers.
|}
See also
Road safety
Traffic enforcement camera
References
Category:Consumer electronics
Category:Traffic law
Category:Radar
